Revert "Explicitly add mranderson middleware"

This was somehow causing all of the non-rewritten dependencies to still be
present in build artifacts. The implicit deprecation warning will be removed in
future versions of Leiningen anyway.

This reverts commit f2b83f8.

Author: cichli

project.clj

@@ -20,11 +20,8 @@
                  ^:source-dep [org.clojure/tools.namespace "0.3.0-alpha4"]
                  ^:source-dep [org.clojure/tools.trace "0.7.10"]
                  ^:source-dep [org.clojure/tools.reader "1.2.2"]]
-  :exclusions [org.clojure/clojure]
-
-  :implicits false
   :plugins [[thomasa/mranderson "0.4.9"]]
-  :middleware [mranderson.plugin/middleware]
+  :exclusions [org.clojure/clojure]
 
   :filespecs [{:type :bytes :path "cider/cider-nrepl/project.clj" :bytes ~(slurp "project.clj")}]